This invention is related to the use of leukemia inhibitory factor (LIF) and other agonists of the LIF receptor, in the regulation of inflammation and pain.
Leukemia inhibitory factor (LIF) belongs to the neuropoietic cytokine family, which also includes ciliary neurotrophic factor (CNTF), oncostatin M (OSM), growth promoting activity, cardiotrophin-1, and interleukin-6 and -11 (IL-6 and IL-11). All of these cytokines are pluripotent, having effects on proliferation and gene expression in a wide variety of cell types in culture. Moreover, all of these cytokines can utilize the same signal transducing receptor subunit, gp130, which exists in a number of different cell types.
LIF has been implicated as having a role in both the neural and immune responses to injury (Patterson P H (1994) Proc Natl Acad Sci USA 91:7833-7835). For example, within the nervous system, LIF mRNA levels dramatically increase soon after injury (Patterson P H (1994) Proc Natl Acad Sci USA 91:7833-7835; Kurek J B, et al, (1996) Neuromusc Disorders 6:105-114; Banner, L R, et al, (1997) Exper Neurol, in press), and experiments with LIF null mutant (knockout) mice demonstrate that LIF is required for the changes in neuronal gene expression that are characteristic of the injury response (Rao M S, et al, (1993) Neuron 11:1175-1185; Corness J. et al, (1996) Exp Brain Res 112:79-88; and Sun Y. Zigmond R E (1996) Eur J Neurosci 8:2213-2220). Following sciatic nerve injury, LIF is required for normal inflammatory cell infiltration, and LIF is directly and indirectly chemotactic for macrophages (Sugiura S. et al., (2000) Eur. J. Neurosci. 12: 457-466; Tofaris G K, et al., (2000) Soc. Neurosci. Abstr., in press). Lack of LIF can also lead to premature neuronal death (Sendtner M, et al, (1996) Curr Biol 6:686-694). Moreover, addition of LIF to severed nerves can enhance nerve regeneration and functional recovery (Tham S, et al, (1997) J Neurosci Res 47:208-215).
Studies have also reported that LIF levels are increased in a variety of animal and human inflammatory conditions (Alexander H R, et al, (1994) Cytokine 6:589-596; Brown et al, (1994) Cytokine 6:300-309; Ulich T R, et al, (1994) Amer Physiol Soc 267:442-446; and Heyman D, et al, (1996) Cytokine 8:410-416). Inflammation of the skin is a serious medical problem. Depending on the country, epidermal irritants and allergic reactions comprise 20-70% of all occupational diseases. There are also chronic skin diseases such as psoriasis, which is one of the most common immune-mediated diseases in humans, affecting 2-3% of the population. In addition, excessive exposure to ultraviolet radiation can cause inflammation as well as local and systemic immunosuppression and skin cancer. In each of these conditions, cytokines play a key role in initiating and maintaining pathophysiology as well as in inducing recovery (Ullrich S. E. (1995) Photochem. Photobiol. 62: 389-401; Asadullah K, et al., (1999) Drugs of Today 35: 913-924; Bonifati C, et al., (1999) Int. J. Dermat. 38: 241-251; Corsini E, et al., (2000) Toxicology 142: 203-211). Of these cytokines, tumor necrosis factor (TNF) and IL-1 are considered to be primary initiators of cutaneous inflammation, with IL-4, -6, -7, -8, -10, -11, IFN-xcex3 and transforming growth factor (TGF)xcex2 also being implicated. For example, in the chronic cutaneous inflammatory condition of psoriasis, a number of type 1 cytokines are up-regulated, including IL-2, IL-6, IL-8, IL-12, IL-18, IFN-xcex3 and TNFxcex1, while relatively low levels of anti-inflammatory cytokines such as IL-IRA and IL-10 have been found (Ullrich S. E. (1995) Photochem. Photobiol. 62: 389-401; Asadullah K, et al., (1999) Drugs of Today 35: 913-924; Bonifati C, et al., (1999) Int. J. Dermat. 38: 241-251; Corsini E, et al., (2000) Toxicology 142: 203-211; Naik S M, et al., (1999) J. Invest. Dermatol. 113: 766-772). The cytokines that play key regulatory roles in this signaling cascade are of clinical interest as potential targets of therapeutic intervention; e.g., subcutaneous delivery of IL-10 or -11 to patients with psoriasis can ameliorate this condition (Asaduliah K, et al., (1998) J. Clin. Invest. 101: 783-794; Trepicchio W L, et al., (1999) J. Clin. Invest. 104: 1527-1537).
Leukemia inhibitory factor is also of interest in this context, as this cytokine can induce pro-inflammatory as well as anti-inflammatory effects, depending on the tissue and the form of perturbation (reviewed in Gradient R, et al., (1999) Stem Cells 17: 127-137). In the periphery, injection of high concentrations of LIF into skin or joints can induce swelling and leukocyte invasion (Carroll G J, et al., (1995) J. Interferon. Cytokine Res. 15: 567-573; McKenzie R C, et al., (1996) Acta Derm. Venereol. (Stockh) 76: 111-114). Injection of high doses of LIF into the ear pinnae of mice increased ear thickness (McKenzie R C, et al., (1996) Acta Derm. Venereol. (Stockh) 76: 111-114), and systemic injection of high levels of LIF induced a prolonged hypersensitivity to mechanical stimulation (Thompson S W N, et al., (1996) Neuroscience 71: 1091-1094).
While these studies implicate LIF as having a role in the nervous and immune systems, there is a need to establish the interactions between the nervous and immune systems during the injury response. Accordingly, it is an object herein to determine the role of LIF in response to or in anticipation of injury, trauma or disorders associated with inflammation and/or pain, and to use LIF to modulate inflammation and pain, individually or together.
It is further an object to use biologically active fragments of LIF and other agonists of the LIF receptor to modulate inflammation and/or pain. It is further an object to administer or upregulate LIF or other agonists of the LIF receptor and particularly the signal transducing receptor subunit gp130, in an individual prior to or simultaneous with activities such as sports, hard labor, or undertaking surgery which generally result in inflammation and pain. It is additionally an object to provide a method of using LIF to prevent and/or reduce the inflammation and/or pain associated with Rheumatoid arthritis.
It is also an object herein to provide methods for screening for modulators of LIF and/or LIF activity, particularly those which enhance the anti-inflammatory activity of LIF.
In accordance with the objectives of the application set forth herein, a method for inhibiting and/or reducing inflammation in an individual is provided. The method comprises administration of leukemia inhibitory factor (LIF) to a cell or an individual in an amount effective to inhibit and/or reduce inflammation.
In one aspect, administration of LIF is prior to an activity or condition which is known to result in inflammation. Alternatively, administration occurs during or preferably, at the onset of the activity or condition.
Administration of LIF in accordance with the present invention is preferably to a site of inflammation or potential inflammation. Administration can be in conjunction with a transdermal formulation, injected or applied topically directly to a site, i.e., an open wound or surgical site. In a preferred embodiment, LIF protein is administered. In another embodiment, nucleic acid encoding LIF is administered, preferably using a viral vector.
The methods provided herein also are directed to the administration of LIF to reduce and/or inhibit pain. The method comprises the administration of LIF to an individual in an amount effective to inhibit and/or reduce the pain.
Methods are also provided herein wherein candidate agents are screened for their ability to modulate the activity of LIF. The method comprises administering LIF to a cell or animal model in the presence of the candidate agent and determining the activity of LIF.